Forty Army Ranger students and four instructors were struck by lightning in Florida during a training program aimed at protecting themselves from a thunderstorm's lightning bolts, the US Army said on Thursday.
All 44 individuals were taken to a local hospital for treatment following the Wednesday afternoon incident at Eglin Air Force Base, in north Florida, the Army said in a statement.
Seventeen students and three instructors remained overnight at the hospital while the remaining students and instructor were treated and released, the statement said.
"The Ranger students and instructors reacted and got everyone proper medical care quickly," said Colonel David Fivecoat, Airborne and Ranger Training Brigade commander.
"Ranger students and instructors are tough, 31 students will return to training tonight (Thursday) and continue with increased medical monitoring as they try to earn their Ranger tab," he said.
Army Rangers are rapidly deployable troops trained for mountain, desert and swamp terrain and often go after special operations targets.
Ranger School is an intense weeks-long combat boot camp.
The students were in day seven of the 10-day training cycle, the Army said.
The Army Times news site said the Ranger trainees were in the "swamp phase" which focuses on waterborne operations.